In his federal constitutional challenge to the state conviction, Sirhan's lawyer asked all the U.S. magistrates and judges in the Central District of California — the Los Angeles area — to withdraw from considering the case.

Sirhan contended that the U.S. attorney in Los Angeles in 1968, William Byrne Jr., played an active role in the state prosecution of his case.

Sirhan's trial lawyer also performed poorly, Sirhan said, because Byrne was threatening to criminally prosecute the trial lawyer on an unrelated matter.

Now Byrne is a senior federal judge in Los Angeles, Sirhan told the Supreme Court.

The magistrate assigned to hear Sirhan's constitutional challenge to his state conviction is a Byrne colleague, Sirhan said, as are all the other federal magistrates and judges in the area.

When Sirhan's motion for a mass judicial withdrawal was denied by the chief judge of the Central District, Sirhan challenged the denial before the 9th U.S. Circuit Court of Appeals. After the appeals court rejected his petition, Sirhan asked the Supreme Court to intervene.

The Supreme Court denied the request Monday in a one-line order.

Sirhan was convicted of shooting Kennedy to death early in the morning of June 5, 1968, in the Ambassador Hotel in Los Angeles.

Kennedy, a U.S. senator from New York and a brother of assassinated President John F. Kennedy, had just claimed victory in the California Democratic presidential primary.

Sirhan was sentenced to death, but his sentence was commuted to 30 years to life after the Supreme Court outlawed the way the death penalty was being applied in 1973. The high court restored the death penalty, with some modifications, in 1976.

Though he has now served more than 30 years in prison, California authorities have refused to grant him parole.